The changelog update script now prevents duplicate entries from being
added. Specifically, it will ensure that if a PR has been referenced
already in an entry, it will not add it again.
This should prevent it from adding duplicate entries for changes that
were cherry-picked into hotfix releases.
Note that this duplication prevention only works for entries containing
a PR number. We don't have any way to prevent duplicate entries yet in
cases where we don't know the associated PR. We will be preventing this
possibility entirely pretty soon in some upcoming release automation
changes though, so I'm not concerned about this omission.
Instead of always placing new changelog entries under the "Current
Develop Branch" header, the changelog script now places them under the
header for the current release if that release has not yet been tagged.
This eliminates one manual step from the release process.
Relates to #10752
Mark Stacey